The Collaborative International Dictionary of English v.0.48:
Yourself \Your*self"\, pron.; pl. Yourselves. [Your + self.]
An emphasized or reflexive form of the pronoun of the second
person; -- used as a subject commonly with you; as, you
yourself shall see it; also, alone in the predicate, either
in the nominative or objective case; as, you have injured
Of which right now ye han yourselve heard. --Chaucer.
If yourselves are old, make it your cause. --Shak.
Why should you be so cruel to yourself ? --Milton.
The religious movement which you yourself, as well as
I, so faithfully followed from first to last. --J. H.